Proximate factors associated with high levels of extraconsort fertilization in polygynous grey seals

Ambs, S.; Boness, Daryl J.; Bowen, W. Don; Perry, EK; Fleischer, Robert C.

doi:10.1006/anbe.1999.1201

Cited by 33 publications

(36 citation statements)

References 44 publications

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“…Using DNA typing, Amos et al (1993) and Ambs et al (1999) have shown that proximity to a female during perioestrus is a reasonable indicator of relative reproductive success in male grey seals although not an assurance of paternity. In this study, given that copulations are rarely observed, female attendance in addition to copulatory behaviour, were used as an index of mating success.…”

Section: Methodsmentioning

confidence: 99%

“…The maximum duration of stay at a site had important consequences for mating success. For Sable Island and North Rona, respectively, Ambs et al (1999) and Amos et al (1993) have shown that c. 60±70% of females are fertilized by the male that guards and defends them against approaches by other males during late lactation. Several studies have found a positive correlation between length of tenure and mating success (Anderson et al, 1975;Boness & James, 1979;Godsell, 1991;Twiss et al, 1994;Tinker et al, 1995).…”

Section: Mating Success and Male Mating Tacticmentioning

confidence: 99%

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A novel mobile approach to investigating mating tactics in male grey seals (Halichoerus grypus)

2001

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Studies of the grey seal Halichoerus grypus mating system, using focal animal sampling constrained by study site location and size, limit the measurement of variation in male mating tactics and success. Using this method, the mating tactics of grey seal males have been classi®ed as either`tenured' or`transient'. Preliminary evidence is presented of wider variation in male mating tactics and success using mobile focalanimal techniques that are not constrained by site, and of the effects of age on behaviour when accounting for body mass. The study was conducted during the breeding seasons of 1997 and 1998 at Sable Island, Nova Scotia. Six young (11±12 years) and ®ve old (20±25 years) males were captured at the beginning of the breeding season, weighed and ®tted with a VHF transmitter and time-depth recorder. Each male was located daily, and a count of late-lactating females within a 10 m radius recorded as a measure of mating potential. Female guarding and observed copulatory attempts were used as a measure of mating success. Mean initial body mass of young males and old males was similar, 291 13 kg and 298 14 kg, respectively. All males changed location during the study period. Young males changed sites more often and moved shorter distances between sites than old males. Estimated mating success varied from probably no matings to a minimum of seven; there were no differences between young and old males. Maximum duration of stay at a site and the number of late-lactating females at a site signi®cantly in¯uenced mating success. All the males except for two young males departed on diving excursions during the breeding season and engaged in deep diving behaviour. Diving behaviour did not differ between the age classes. Our results indicate that the current classi®cation of mating tactics in grey seal males is an oversimpli®cation. Preliminary data show that age may account for some of the variation in male behaviour on land and mating success, but not for behaviour at sea.

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Section: Methodsmentioning

confidence: 99%

Section: Mating Success and Male Mating Tacticmentioning

confidence: 99%

A novel mobile approach to investigating mating tactics in male grey seals (Halichoerus grypus)

2001

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“…Behavioural estimates of success are inadequate for grey seals on Sable Island because extra-consort fertilizations are known to occur (Ambs et al 1999). Thus, our original intention in this study was to provide estimates of reproductive success for each male.…”

Section: Measures Of Mating Successmentioning

confidence: 98%

“…Males that defend consorts have a higher probability of siring offspring than those that attempt to mate with departing females (Lidgard et al 2004). Other mating tactics may occur in this population, such as mating with females that are being defended by a neighbouring male, mating with females after a brief period of defence, and mating with females while at sea (Ambs et al 1999;Lidgard et al 2003). However their success is not known and in the case of the former two tactics, might simply be failed attempts at the consort tactic.…”

Section: Introductionmentioning

confidence: 95%

Longitudinal changes and consistency in male physical and behavioural traits have implications for mating success in the grey seal (Halichoerus grypus)

2012

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We examined age-related changes and consistency in physical and behavioural traits of 20 male grey seals (Halichoerus grypus (Fabricius, 1791)) and implications for a proxy of mating success (number of oestrous females attended) over four successive breeding seasons on Sable Island, Canada. Across the study, young males (10-15 years) gained body mass, while old males (23-31 years) lost body mass. Body length was an important determinant of tenure (time spent at a site among females) and males of all ages exhibited a high level of consistency in duration of tenure (r = 0.40-0.50). In young males, our proxy of success showed a strong relationship with arrival body mass and also exhibited a high level of consistency (r = 0.50). None of the physical traits measured explained variation in success by exhibiting mating tactics that did not involve tenure, which is likely due to the opportunistic nature of those tactics. Whereas young male grey seals exhibited age-dependent improvements in success owing to changes in their physical state, later in life physical traits were less influential and suggest that nonphysical traits may compensate for a deteriorating physical state and its impact on male success.Résumé : Nous avons examiné les changements associés à l'âge et la cohérence des caractères physiques et comportementaux de 20 phoques gris mâles (Halichoerus grypus (Fabricius, 1791)) et leur signification en ce qui concerne une variable substitutive du succès d'accouplement (le nombre de femelles en oestrus accouplées) pendant quatre saisons de reproduction successives dans l'île de Sable (Canada). Durant l'étude, la masse corporelle des jeunes mâles (de 10 à 15 ans) a augmenté alors que celle des vieux mâles (de 23 à 31 ans) a diminué. La longueur du corps était un important déterminant de la rési-dence (le temps passé en un lieu parmi des femelles) et les mâles de tout âge présentaient un degré élevé de cohérence relativement à la durée de la résidence (r = 0,40 à 0,50). Chez les jeunes mâles, notre variable substitutive de succès présentait un fort lien avec la masse corporelle à l'arrivée ainsi qu'un degré de cohérence élevé (r = 0,50). Aucun des caractères physiques mesurés n'explique les variations du succès découlant de tactiques d'accouplement ne comprenant pas la résidence, ce qui est probablement attribuable au caractère opportuniste de ces tactiques. Si les jeunes phoques gris présentent des améliorations du succès qui dépendent de l'âge en raison de changements à leur état physique, l'incidence des caractères physiques est moins importante à des âges plus avancés, ce qui porte à croire que des caractères non physiques pourraient compenser la détérioration de l'état physique et son impact sur le succès des mâles.

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“…The strongest support comes from studies at the terrestrial breeding sites of North Rona and the Isle of May in the U.K., where a large proportion of pups born are not sired by males sampled onshore (Worthington Wilmer et al 1999). Ambs et al (1999) have also shown that on Sable Island, 43% of pups are not sired by the consort male. Although some extra-consort fertilizations are likely to occur on land, others may occur at sea.…”

Section: Discussionmentioning

confidence: 94%

Diving behaviour during the breeding season in the terrestrially breeding male grey seal: implications for alternative mating tactics

Lidgard¹,

Boness²,

Bowen³

et al. 2003

Can. J. Zool.

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Abstract:We examined the diving behaviour of breeding male grey seals (Halichoerus grypus) at Sable Island, Nova Scotia, from 1997 to 2001. The proportion of time spent at sea varied between 0 and 78% (N = 30). Males engaged in deep (43.4 ± 3.3 m (mean ± SE), N = 27) diving, and these dives were clustered into bouts, which mostly occurred during long trips (62.2 ± 14.7 h). We suggest that males spent time foraging during deep dives. Shallow diving (5.9 ± 0.1 m, N = 27) accounted for 40.8% of dives, which were also clustered into bouts that mostly occurred during short trips (2.1 ± 0.37 h). We suggest that shallow diving comprised a suite of behaviours, but included little foraging behaviour. Phenotypic traits had little influence on diving behaviour. Further work is required to understand the extent to which foraging behaviour enhances reproductive success, and whether shallow diving is a component of the mating tactics of male grey seals at Sable Island.Résumé : Nous avons étudié le comportement de plongée de mâles du phoque gris (Halichoerus grypus) en période de reproduction à l'île de Sable, Nouvelle-Écosse, de 1997 à 2001. La fraction du temps passé en mer varie de 0 à 78 % (N = 30). Les mâles entreprennent des plongées profondes (43,4 ± 3,3 m (moyenne ± erreur type), N = 27) qui sont regroupées en épisodes, surtout durant les voyages prolongés (62,2 ± 14,7 h). Nous croyons que les mâles passent une partie du temps de ces plongées profondes à la recherche de nourriture. Les plongées moins profondes (5,9 ± 0,1 m, N = 27) représentent 40,8 % des plongées et elles se font aussi par épisodes, principalement durant les voyages courts (2,1 ± 0,37 h). Nous pensons que les plongées peu profondes consistent en une suite de comportements, mais avec peu de recherche de nourriture. Les caractéristiques phénotypiques influencent peu le comportement de plongée. Seules des études additionnelles permettront de comprendre comment le comportement de recherche de nourriture contribue à améliorer le succès de la reproduction et de savoir si les plongées de faible profondeur font partie des tactiques d'accouplement chez les phoques gris de l'île de Sable.[Traduit par la Rédaction] 1033 Lidgard et al.

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Proximate factors associated with high levels of extraconsort fertilization in polygynous grey seals

Cited by 33 publications

References 44 publications

A novel mobile approach to investigating mating tactics in male grey seals (Halichoerus grypus)

A novel mobile approach to investigating mating tactics in male grey seals (Halichoerus grypus)

Longitudinal changes and consistency in male physical and behavioural traits have implications for mating success in the grey seal (Halichoerus grypus)

Diving behaviour during the breeding season in the terrestrially breeding male grey seal: implications for alternative mating tactics

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